Chloroselenobenzene → 2',4'-Dichloro-2-phenylselenenyl-2-(1H-1,2,4-triazol-1-yl)propiophenone

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Reaction Steps

To a solution of 2',4'-dichloro-2-(1H-1,2,4-triazol-1-yl)propiophenone (3 g, 11 mMole) in tetrahydrofuran (60 ml) cooled to 5° was added sodium hydride as a 50% by weight dispersion in oil (0.68 g of said dispersion which contained 14 mMole of sodium hydride). Thirty minutes later phenylselenenyl chloride was added in four equal portions over five minutes (2.95 g, 15.4 mMole). Fifteen minutes later glacial acetic acid was added (1.5 ml) and the mixture was poured into water (100 ml). Excess solid sodium bicarbonate was added to basify the solution, which was then extracted with ethyl acetate (3×50 ml). The organic extracts were combined, washed with saturated saline solution (3×50 ml) and dried over anhydrous magnesium sulphate. Evaporation gave an impure oil, weight 5.4 g. Purification was carried out by `flash` column chromatography under slight pressure (2 p.s.i.) on a `Merck Kieselgel 60` (trade mark) 230-400 mesh silica-packed column, eluting with ether and 40°-60° petrol (1:1). The appropriate fractions after collection and evaporation gave a solid which was recrystallized from cyclohexane to give the pure title compound, 2.57 g, m.p. 84°-86° (47% yield).

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